Diazodinitrophenol



v50 in my improved process, building up all crystal In carrying out the method in accordance with 50 55 particles of diazodinitrophenol, which form dust concentration as high as 9.7% has been success- 55 man Ap..25,1939 1 2,155,579

. UNITED STATES PATENT OFFICE.

DIAZODINITROPHENOL AND METHOD OF PREPARATION OF THE SALE.

Leon W. Babcock, Kenvil, N. J., assignor to Hercules Powder Company, Wilmington, Del., a corporation of Delaware No Drawing. Application December 21, 1937, Serial No. 181,028

5 Claims. (01. 260-141) This invention relates to a method for the proon drying, which fine particles are caused by very duction of diazodinitrophenol, and more particurapid diazotization reaction. Dust in dry diazolarly to a method whereby diazodinitrophenol dinitrophenol is a very serious disadvantage, not may be produced directly in. a free-flowing form, only that it hinders free-flowing in machine 5 adapted for machine loading into blasting caps. loading, but constitutes a serious hazard when 5 Diazodinitrophenol has long been known, as settling on various apparatus used in the manuhave various methods for its production, e. g. facture of blasting C l United States Letters Patent to Dehn, Nos. Also, the process in accordance with my in- 1,404,08'7; 1,428,011; 1,460,708. Diazodinitrovention premits the production of diazodinitro- 0 phenol constitutes a very valuable explosive for phenol of uniform and controlled density, ahighly use in blasting caps, but, as produced in accordimportant factor in the manufacture of blasting ance with the above processes, it is not freecaps. Diazodinitrophenol manufactured in acfiowing, but composed of needle-like crystals, and cordance with processes heretofore known has hence not adapted to machine loading of blasting suffered from unexpected and uncontrollable Vacaps. riations in density. Since blasting caps are nec- 15 Methods of preparation of free-flowing diazoessarily loaded by machine and by measured dinitrophenol are known, e. g. in accordance with volume of explosive charge, it is evident that a United States Letters Patent Re. 19,645 to Hanlow density diazodinitrophenol will produce a cock and Pritchett, disclosing a slow rate .of addiblasting cap having therein a less weight of tion of acid to the diazotization mixture, and charge, and vice versa. Heretofore, it has been 20 Patent No. 2,103,926 issuedDecember 28, 1937 necessary to blend various lots of diazodinitroto Harvey B. Alexander disclosing diazotization in phenol, in accordance with their density, in order. the presence of certain compounds which prevent I to produce a material of uniform density suitable the formation of needle-like crystals. for loading into blasting caps. The use of my In accordance with this invention a novel, simimproved process, producing a product of uniform 25 ple and economical method is provided for the density, renders such blending unnecessary exproduction of diazodinitrophenol, in which diazocept in unusual cases. dinitrophenol may be prepared directly in free- The injector or atomizer used in my process flowing form, without the use of any added maneed not be of any particular shape or form, but

terials and without the excessive supervision reneed only be adapted to atomize the acid used 30 quired by the gradual addition of acid in the Haninto fine droplets and force the same under the cock and Pritchett process. surface of the diazotizing mixture. It should be In practicing the process in accordance with of acid-resisting material, e. g. glass, porcelain, this invention, the acid is added to the diazotizastoneware, or the like, because it must handle tion mixture by means of an atomizer or spraydilute mineral acids. I prefer to use glass. as the 35 ing device, operated by the use of compressed air material of construction, for the reason that or other gas inert to the ingredients of the diazoporcelain or stoneware are liable to chip or wear tization mixture, such as carbon dioxide, nitrogen, and introduce grit into the material formed. The

or the like. atomizer is preferably placed a short distance be- While the theory of the operation of my new low the surface of the diazotizing mixture. 40 process has not been clarified, I am of the opinion In the practical adaptation of my invention,

that the advantage of my improved process lies any suitable salt of picramic acid may be used, in the elimination of local regions of high acid e. g. sodium picramate, ammonium picramate, concentration in the diazotizing bath, practically magnesium picramate. Likewise, various niimpossible to overcome with processes used heretrites, such as sodium nitrite, potassium nitrite, 45

tofore and involving gradual flow of acid to the barium nitrite. The acid used may be any suitdiazotization bath. Since rate of diazotization able acid adapted to effect diazotization of the depends upon acid concentration, reaction propicramate and nitrite, such as hydrochloric, sulgresses uniformly throughout the entire mixture furic, phosphoric, acetic, etc.

agglomerates uniformly at the same rate and my invention, the picramate and nitrite will be producing uniform grain size. in solution or in suspension, or partly in solu- Moreover, the elimination of local regions of tion and partly in suspension, in water. For high acidity prevents the formation of very fine example, a suspension of sodium picramate of fully diazoti'zed by the method in accordance with my invention, but I do not limit my invention to this percentage. The solution or suspension of picramate will, desirably, be substantially neutral, and the concentration of the picramate therein may vary widely. The temperature during the diazotization will, desirably, be maintained by any suitable means within the range of about 10 C. to about 16 C. The diazotizating mixture will be suitably stirred or agitated, e. g. by a rotating stirrer or by a current of air or gas inert to the mixture being diazotized.

As illustrative of the practical application of the method in accordance with this invention, about 61.2 pounds, dry weight, of water-wet sodium picramate, screened to remove foreign material, is charged into a diazotizing tub, preferably of wood, fitted with a stirrer, and about 90 gallons of water added. About 19 pounds of sodium nitrite, dissolved in about 10 gallons of water, are then run into the diazotizing tub, and the stirrer started. The temperature of the mixture is then brought to the desired point, e. g. about 15 C. Then about 40 liters of 20% hydrochloric acid are sprayed or atomized into the mixture, under the surface of said mixture, by the use of the atomizer heretofore described, preferably at such a rate as to require about 275 minutes to add the entire amount of acid. The rate of addition of the acid may be varied considerably, depending upon the pressure of the compressed gas used in the atomization. About 5 minutes after completion of addition of the acid, the mixture is tested with potassium iodide-starch test paper, and, if such test shows a strong, positive indication of excess of nitrous acid, diazotization of the sodium picramate is complete.

Stirring is then stopped and the mixture placed on a suction filter, the mother liquor drawn off, and the diazodinitrophenol washed with water.

The method in accordance with this invention is not dependent upon the use of any particular form or size of apparatus, means for cooling, or the like.

What I claim and desire to protect by letters Patent is:

1. The method for producing diazodinitrophenol in a free-flowing form which includes diazotizing a picramate in the presence of a nitrite and water by adding thereto acid in atomized form beneath the surface of said picramate, nitrite and water.

2. The method for producing diazodinitrophenol in a free-flowing form which includes diazotizing a substantially neutral mixture of a salt of picrarnic acid, a nitrite, and water by addition thereto of an acid in atomized form beneath the surface of said picramate, nitrite and water.

3. The method for producing diazodinitrophenol in a free-flowing form which includes diazotizing a picramate by addition thereto of an acid in atomized form beneath the surface of the reaction mixture, in the presence of a nitrite and water, while maintaining the tern perature of the reactants within the range of about 10 C. to about 16 C.

4. The method for producing diazodinitrophenol in a free-flowing form which includes diazotizing sodium picramate by addition thereto of hydrochloric acid in atomized form beneath the surface of the reaction mixture, in the presence of sodium nitrite and water.

5. The method for producing diazodinitrophenol in a free-flowing form which includes diazoting sodium picramate by addition thereto of hydrochloric acid in atomized form beneath the surface of the reaction mixture, in the presence of sodium nitrite and water, while maintaining the temperature of the reactants within the range of about 10 C. to about 16 C.

LEON W. BABCOCK. 

